feat(installer): add WPF installer/configurator project

Standalone WPF app (ClaudeDo.Installer) that handles full installation
and ongoing configuration of ClaudeDo. Two modes: wizard for first run,
tabbed settings panel for subsequent launches. Page-based extensibility
via IInstallerPage interface — adding new config sections requires only
one new class.

Install pipeline: dotnet publish, deploy binaries, write configs, init
DB (via SchemaInitializer from ClaudeDo.Data), register Windows Service,
create shortcuts. Dark theme matching the Avalonia app (forest teal accent).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Installer/Pages/PathsPage/PathsPageView.xaml

@@ -0,0 +1,41 @@
+<UserControl x:Class="ClaudeDo.Installer.Pages.PathsPage.PathsPageView"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:local="clr-namespace:ClaudeDo.Installer.Pages.PathsPage"
+             d:DataContext="{d:DesignInstance local:PathsPageViewModel}"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             mc:Ignorable="d">
+
+    <ScrollViewer VerticalScrollBarVisibility="Auto">
+        <StackPanel MaxWidth="520">
+            <TextBlock Text="Data Paths" FontSize="18" FontWeight="SemiBold" Margin="0,0,0,4"/>
+            <TextBlock Text="Configure where ClaudeDo stores its data."
+                       Foreground="{StaticResource TextSecondaryBrush}" Margin="0,0,0,20"
+                       TextWrapping="Wrap"/>
+
+            <Label Content="Database Path"/>
+            <TextBox Text="{Binding DbPath, UpdateSourceTrigger=PropertyChanged}" Margin="0,0,0,12"/>
+
+            <Label Content="Log Directory"/>
+            <TextBox Text="{Binding LogRoot, UpdateSourceTrigger=PropertyChanged}" Margin="0,0,0,12"/>
+
+            <Label Content="Sandbox Root"/>
+            <TextBox Text="{Binding SandboxRoot, UpdateSourceTrigger=PropertyChanged}" Margin="0,0,0,12"/>
+
+            <Label Content="Worktree Strategy"/>
+            <ComboBox SelectedItem="{Binding WorktreeRootStrategy}" Margin="0,0,0,12">
+                <sys:String xmlns:sys="clr-namespace:System;assembly=mscorlib">sibling</sys:String>
+                <sys:String xmlns:sys="clr-namespace:System;assembly=mscorlib">central</sys:String>
+            </ComboBox>
+
+            <StackPanel Visibility="{Binding IsCentralVisible, Converter={StaticResource BoolToVisConverter}}">
+                <Label Content="Central Worktree Root"/>
+                <TextBox Text="{Binding CentralWorktreeRoot, UpdateSourceTrigger=PropertyChanged}" Margin="0,0,0,12"/>
+            </StackPanel>
+
+            <TextBlock Text="{Binding ValidationError}" Foreground="{StaticResource ErrorBrush}" FontSize="11"
+                       Visibility="{Binding ValidationError, Converter={StaticResource NullToCollapsedConverter}}"/>
+        </StackPanel>
+    </ScrollViewer>
+</UserControl>